Re: Bicyclist decapitated

On Mon, 29 Apr 2024 12:18:50 -0400, Frank Krygowski
<frkrygow@sbcglobal.net> wrote:

On 4/28/2024 11:40 PM, Jeff Liebermann wrote:

 
I beg to partially differ.  If we assume that all the known elements
are present in roughly the same distributions throughout the universe,
there's a good chance that self-replicating life processes will be
built using the same elements as on planet Earth.  "Carbon atoms are
unique because they can bond together to form very long, durable
chains that can have branches or rings of various sizes and often
contain thousands of carbon atoms."
<https://www.nature.com/articles/139290a0.pdf>
The emergence of life is possible with comparatively inferior elements
but the main building block will mostly likely be a stable atom that
will build the strongest and move versatile bonds to other atoms.

Agreed. I confess to low talent for chemistry. But I've not yet heard of
a detailed proposal for a chemistry of life built on anything but carbon.
>
If someone here has such a proposal, I'd happily run it by the chemists
in our family.

Did you search for "silicon based life"?  There is quite a bit on the
possible existence of Silicon based life:
<https://www.google.com/search?q=possibility+of+silicon+based+life>

"On the Potential of Silicon as a Building Block for Life"
<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7345352/>
We're probably not going to find silicon based life on a water planet:
"We find that in a water-rich environment silicon’s chemical capacity
is highly limited due to ubiquitous silica formation..."
However, if the planet has sulfuric acid oceans:
"Sulfuric acid, surprisingly, appears to be able to support a much
larger diversity of organosilicon chemistry than water."
The section on "carbon planets" is also interesting.

If silicon based life is not your cup of tea, here is a list of
alternatives:
"Hypothetical types of biochemistry"
<https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry>
We already have a life form on Earth that's built on silicon.  Marine
diatoms extract silicon oxide from sea water and use it to build their
sea walls. 
<https://en.wikipedia.org/wiki/Hypothetical_types_of_biochemistry#Silicon_biochemistry>

Note that astronomy has shown that carbon is about 10 times more
abundant in the universe than silicon.  If carbon based life were to
compete with silicon based live for an ecological niche, I would bet
that carbon would win.  However, not on planet earth, where silicon is
28% of the earth's crust and carbon is only 0.02%"
<https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth%27s_crust>

"What If Alien Life Were Silicon-Based?"
<https://www.youtube.com/watch?v=469chceiiUQ>
The author proposes that the silicon based life is possible, but only
in very specialized environments.

Lots of possibilities, but no "detailed proposal".  That's because we
would need to build a self replicating structure based on silicon
before we can speculate on the chemistry involved in energy
production, assimilation of food, breaking down the food into
something that could be oxidized, providing a template for
self-reproduction (RNA/DNA), etc.  One step at a time please.


--
Jeff Liebermann                 jeffl@cruzio.com
PO Box 272      http://www.LearnByDestroying.com
Ben Lomond CA 95005-0272
Skype: JeffLiebermann      AE6KS    831-336-2558